Manufacture of steel.



UNTTnn sTATEs T oTTien;

JOHN WATSON SPENCER, OF NEWCAsTLE-UPON-TYNE, ENGLAND.

MANUFACTURE oF sTEEi...

Specification of Letters Patent.

Patented May 29, race;

' Application filed July 31,1903. Serial No. 167,782.

To all whom it may concern.- i- Be it known that I, JOHN WATSON SPEN- OER, steel manufacturer, a subject of the King of Great Britain, residing at Newburn,

facture of improved steel wherein valuable properties are obtained renderingsuch steel of greater utility for boiler-plates, shipplates, and all classes of forgings, such as are made from so-called mild and medium hard steel.

Accordin to my invention I add to all kinds of mi d and medium hard steels containing carbon from .05 per cent. up to .25

per cent. ,a larger pro ortion of silicon than as hitherto been use commercially.

It is common knowledge that silicon has been and is used for such purposes as conferring solidity upon steel castings and ingots and in much larger proportions for the manufacture of the harder classes of steel, such as spring-steel and tool-steel.

It is the special object of my invention to utilize the valuable properties conferred upon mild and medium hard steels by the addition of proportions of silicon varying from .75 up to two per cent. By this means the tensile strength and elastic limit of the resulting steel are enormously increased Without impairing its ductility, thus rendering it of much greater value for many urposes.

Not only does the steel ma e according to my invention possess improved strength and ductility, but it also ossesses other marked .physical properties 0 advantage which are shown by the bending and fatigue tests. For ship-plates the strength is so much increased that the thickness of the plates may be so much reduced as to make a great difference in the cost of construction and carryingpower of the vessels. For boiler-plates and forgings the strength is so much increased that an increased factor of safety may beobtained where it may not be considered expedient to reduce the weight.

.My present invention consists, therefore, in utilizing this valuable propertyof silicon and applying it to obtain such results as are only at present attainable commercially by the use of nickel, which is much more expensive to add than silicon and which is attended by certain disadvantages not possessed by the silicon.

One of the great advantages in the use of silicon in such proportions as are hereinbefore specified for increasing the strength without loss of ductility is that plates and forgings may be obtained ractically free from surface defects, a wefi-known difiiculty in the use of nickel for such a urpose. The steel which has been improved by the addition of silicon is also easily welded, which renders it' particularly suitable for lates.

Hitherto the s ecial a dition of such large proportions of si 'con as are described in my mvention has been of scientific interest only, and to the best of my knowledge no one has yet attem ted to apply it -commercially to improve t e milder ualities of steel at resent in use, and it is t is which I particu arly claim to have discoyered. In carrying out my invention melt a charge of suitable materia s, such as scrap and pig iron, either alone or as a mixture in a crucible, open hearth, or other furnace or Bessemer or other converter. After the charge has been deqarbonized and refined to'the desired extent I then introduce the desired proportion of silicon or silicon alloy either into the furnace or into the ladle, after which themixture is cast into ingots or other desired form. In making my im roved steel in this manner manganese may e added in the usual way, or in certain cases it may be dis ensed with.

aving now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I. declare that what I claim is The herein-described process consisting in .melting a charge of iron normally containing from .05 per centum to .25 per centum of carbon and maintaining the charge in a melted condition, and introducing into the molten.

mass .75 per centum to two per centum of silicon to produce a modified steel for use 1n making plates, forging steels and the like.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

JOHN WATsoN sPENcER.

Witnesses: NED. V. BROWN, A. H. Dickinson.

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